﻿the 
  Gulf 
  of 
  Manaar. 
  S3 
  

  

  placed 
  more 
  or 
  less 
  at 
  right 
  angles 
  to 
  the 
  long 
  axis 
  of 
  the 
  

   fibre, 
  so 
  as 
  to 
  echinate 
  it, 
  usually 
  in 
  irregular 
  groups. 
  

  

  The 
  main 
  skeleton 
  is 
  a 
  rectangular 
  network 
  of 
  stout 
  pri- 
  

   mary 
  and 
  secondary 
  fibres, 
  the 
  primaries 
  measuring 
  about 
  

   0*14 
  and 
  the 
  secondaries 
  about 
  O084 
  millim. 
  in 
  diameter. 
  

   Both 
  primaries 
  and 
  secondaries 
  consist 
  of 
  a 
  large 
  amount 
  of 
  

   clear 
  transparent 
  spongin, 
  with 
  an 
  axial 
  core 
  of 
  slender 
  

   spicules 
  multiserially 
  arranged. 
  The 
  spicules 
  are 
  numerous 
  

   in 
  both 
  sets 
  of 
  fibres, 
  but 
  more 
  so 
  in 
  the 
  primaries 
  than 
  in 
  

   the 
  secondaries. 
  Numerous 
  spicules 
  occur 
  scattered 
  outside 
  

   the 
  fibres. 
  

  

  The 
  spicules 
  are 
  slightly 
  curved, 
  slender 
  oxea, 
  gradually 
  

   sharp-pointed 
  at 
  each 
  end, 
  measuring 
  about 
  0'084 
  by 
  0*0035 
  

   millim. 
  

  

  Gelliodes 
  carnosa, 
  n. 
  sp. 
  (PI. 
  IV. 
  fig. 
  7.) 
  

  

  Sponge 
  erect, 
  sessile, 
  more 
  or 
  less 
  lamellar, 
  proliferous 
  ; 
  

   sometimes 
  rising 
  into 
  short 
  tubular 
  processes. 
  The 
  arrange- 
  

   ment 
  of 
  the 
  oscula 
  and 
  oscular 
  tubes 
  gives 
  to 
  the 
  sponge 
  a 
  

   very 
  characteristic 
  appearance. 
  The 
  oscula 
  are 
  very 
  nume- 
  

   rous 
  and 
  occur 
  chiefly 
  on 
  the 
  margins 
  of 
  the 
  sponge, 
  but 
  also 
  

   on 
  isolated 
  papillaj. 
  They 
  average 
  2 
  to 
  3 
  millim. 
  in 
  dia- 
  

   meter 
  and 
  lead 
  into 
  long, 
  narrow, 
  vertical 
  oscular 
  tubes. 
  The 
  

   presence 
  of 
  these 
  tubes 
  causes 
  the 
  surface 
  of 
  the 
  lamellee 
  in 
  

   which 
  they 
  lie 
  to 
  be 
  more 
  or 
  less 
  ribbed 
  vertically, 
  so 
  that 
  

   the 
  course 
  of 
  an 
  oscular 
  tube 
  can 
  be 
  traced 
  for 
  some 
  distance 
  

   by 
  means 
  of 
  the 
  rounded 
  ribs 
  on 
  the 
  surface. 
  The 
  largest 
  

   specimen 
  is 
  180 
  millim. 
  high 
  by 
  200 
  millim. 
  broad. 
  The 
  

   thickness 
  of 
  the 
  actual 
  lamellae 
  is 
  about 
  6 
  or 
  7 
  millim. 
  

  

  The 
  colour 
  in 
  the 
  living 
  state 
  was 
  grey 
  and 
  it 
  is 
  also 
  

   brownish 
  grey 
  when 
  dry. 
  The 
  surface 
  is 
  smooth 
  but 
  uneven, 
  

   with 
  rather 
  a 
  fleshy 
  appearance 
  ; 
  in 
  spirit 
  it 
  appears 
  glabrous. 
  

   The 
  texture 
  is 
  tough 
  and 
  resilient. 
  

  

  The 
  skeleton 
  is 
  very 
  strongly 
  developed, 
  composed 
  of 
  a 
  

   very 
  close, 
  more 
  or 
  less 
  regularly 
  rectangular 
  reticulation 
  of 
  

   unusually 
  stout 
  horny 
  fibre. 
  The 
  primary 
  lines 
  have 
  a 
  

   multispicular 
  core 
  of 
  oxeote 
  spicules, 
  while 
  the 
  secondaries 
  

   have 
  fewer 
  spicules. 
  In 
  some 
  parts 
  the 
  arrangement 
  of 
  the 
  

   skeleton 
  becomes 
  less 
  regular, 
  but 
  it 
  is 
  throughout 
  charac- 
  

   terized 
  by 
  a 
  very 
  strong 
  development 
  of 
  spongin. 
  

  

  Spicules. 
  — 
  (a). 
  Megasclera 
  : 
  — 
  Small, 
  usually 
  slightly 
  

   curved, 
  gradually 
  sharp-pointed 
  oxea 
  (fig. 
  7, 
  a, 
  b), 
  measuring 
  

   about 
  0-126 
  by 
  0-006 
  millim. 
  

  

  (b). 
  Microsclera 
  : 
  — 
  Very 
  small 
  and 
  very 
  slender 
  sig.nata 
  

   (fig. 
  7, 
  c), 
  about 
  0'017 
  millim. 
  long; 
  visible 
  after 
  soaking 
  

  

  